Bucket for elastic-fluid turbines.



No. 846,739. PATENTED MAR. 12, 1907. E. H. FARQUHAR. BUGKEITS FOR ELASTIC FLUID TURBINES.

APPLICATION FILED JULY 21, 1906.

2 SHEETS-SHEETI. l5

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No. 846,739. PATENTED MAR. 12, 1907.

E. H. FARQUHAR.

BUGKETS FOR ELASTI UID TURBINES.

APPLICATION FILE m1, 1906.

2 SHEETS-SHEET 2.

VJ In may EDMUND I-I. FARQUHAR, OFSCHENECTADY, NEW YORK, ASSIGNOR TO GEN- ERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

BUCKET FOR ELASTIC-FLUID TURBlN-ES.

Specification of Letters Patent.

. Patented March 12, 1907.

Application filed July 21. 1906- SerialNo. 32.7.177-

useful Improvements in Buckets for Elastic Fluid Turbines, of which the following is a specification.

This invention relates to the buckets, blades, or vanes of elastic-fluid turbines; and its object is to provide an improved mode of securing separately-formed buckets to a seg, mental or other base or'support.

The invention consists in making a dovetail or undercut groove in the base or support and forming each bucket with a dovetail or flanged shank adapted to be slipped into said groove from one end thereof, spacing-blocks being interposed between the shanks on the buckets, and when a section or segment of the entire base is filled with buckets and blocks the metal of the'base segment or su port is upset or riveted around the ends of t e groove to force the buckets and the'spacing devices into. engagementwith each other and secure. the parts firmly together. t

. For convenience I shall show and describe the invention in connection with a bucketwheel, though it will be understood that it is equally applicable to the securing of intermediate buckets to their supports.'

In the accompanying drawings, Figure 1 is a cross-section of a bucket-wheel, showing the ends of two base-segments and the buckets inserted therein. Fig. 2 is a 'side view, partly in section, showing the joint between two base-segments. Fig. 3 is a crosssection transverse to the axes of the blades on the line, 3 3, Fig. 2. Fig. 4 is a perspective view of the filling-block; Fig. 5, 'a perspective view. of a spacing-block. Fig. 6 is a cross-section of the bar from which the spacing-blocks are cut. Fig. 7 is a top plan view of such a'bar, and .Fig. 8 shows a modified construction of wheel and bucketsupport.

The base-segments L are ofany desired length and are curved to fit the periphery of the bucket-wheel 2. Each segment has a flange 3 lying against the face of the Wheel and a lip or rib 4 engaging with a groove in the wheel to resist the centrifugal force developed at high speeds. Whentwo basesegments are placed on opposite sides of the bucket-wheel, they are preferably secured thereto by through-rivets 5, passing through the flanges 3 and the wheel 2. The heads of the rivets are countersunk flush with the surfaces of the flanges to reduce rotation losses.

In the peripheral surface of each segment rower at the throat t' an at the bottom'and is preferably of a dovetail form, as shown. Into this groove are slid the dovetail or flanged shanks 7 on the inner ends of the independently-formed buckets,: blades, or vanes 8. extruded metal, so that they are of uniform cross-section and have smooth-finished sur faces. 1 The shank is formed by cuttin away portions of the bucket at one end t ereof, preferably insuch a manner that the bu ckets stand not quite square across the base-seg-' ment, but with one edge in advance of the other, as shown in Fig. 3.

In order to maintain the buckets apart at the proper distance, spacing-blocks 9 are in-, terposed between them. These blocks are trapezoidal or- T-s'h'faped in cross-section, so

' that they fill the groove inthe base-segment and lie flush withits top. One end lOis con-- vex to fit into the curve of the adjacent bucket-shank andithe other end 11 is concave to fit the convex back of the" next bucket-shank.

At the end of each base-segment a fillingbl'ock 12 is inserted, having a flat end to lie nearly flush with the "end of said segment. The space-blocks 9 are made, preferably, of the same alloy as the buckets in order that they may have the same rate of expansion and contraction; but the filling-blockslZ are made of harder metallike the base-segments, (preferably ste'el,) so as toafiord a rigid abut ment when the metal around the end of the roove in said segment is upset to se'curethe uckets and blocks in place. The upsettin is done by means of a suitable punch, whic forms deep incisions 13 in the metal on lines parallel with the sides and bottom of the groove 6 and crowds a lip 14, of metal, over and against the flat face ofthe filling-block 13 at one end of the base-support. and

against the shank of the end bucket at the other end thereof.

The buckets are provided with the usual cover or shrouding 15.

is cuta longitudinal roove 6, whichisnar- :I prefer to make these buckets of blocks 9.

between the buckets-that is, the pitch of the bucket-Wheel-will be varied. By varyin bloc s will cause the buckets tovary more or less from a position at right angles to the longitudinal 'axis of the groove 6. Thus the block a in Fig. 7 is similar to the ones used in Fig. 3 The block b will skew the buckets still further, while the block 0 will cause the buckets to stand square across the grooves should such an arrangement be desired.

Fig. 8 shows a modification in which the buckets 19 are attached to a bifurcated base .20, which straddles the rim of the bucketwheel 21- and is secured thereto by rivets 22 or otherwise, thus providing for only one row of buckets in the plane of the wheel. The buckets 19 are secured to the base'20 in the same manner as the buckets 8 are secured to the bases 1.

By the construction above set forth the bases or other supports can be made of hard metal, such as steel, which is well qualified to withstand the severe strains to which the wheel is subjected and will not yield or be de- I flected even when the base se ments are secured to the side ofithe whee as in Fig. 1. Moreover, the radial pull on the buckets, due to centrifugal force, is in direct line with the shanks, and the trapezoidal or undercut crosssection of the groove and shanks distributes this tensional strain equally on both sides, so-

that the buckets do to tilt edgewise. I

In accordance with the provisions of the patent statutes I have described the principle not have any tendency of operation of my invention, together with the apparatus which I now consider to repre sent the best embodimentthereof; but I desire to have it understood that the apparatus the location of the curved lines the.

being upset to secure the parts together.

2. The combination with a base having a dovetail or undercut groove, of a plurality of separately-formed buckets of uniform crosssection and cut away at one end to form shanks fitting saidgroove, spacing-blocks in said groove flush with the surface of the base and having curved ends fitting against the bucket-shanks, and lips upset at the ends of the groove to hold the parts together.

3. The combination with a base having a dovetail or undercut groove, of a plurality of separately-formed buckets of uniform cross-f section and cut away at one end to form' shanks fitting said groove, spacing-blocks of the same material as the buckets fitted into said groove and fitting the curves of said bucket-shanks, a filling-block at the end of the groove of substantially the same material as the base, and incisions in the ends of the base forming upset lips to hold the parts together.

v 4. In an elastic-fluid turbine, the combination of a bucket-support having a groove formed therein which is narrower at the throat than at the bottom, buckets having proiections thereon which enter the groove and are retained in place by the walls thereof and devices for spacing the buckets apart to preserve .the proper pitch, the ends of the support being riveted over to force the buckets and the spacing devices into engagement with each other and also to secure them rigidly in said support.

In witness whereof I have hereunto set my hand this 20th day of July, 1906.

EDMUND H. FARQUHAR.

Witnesses:

' BENJAMIN B. HULL,

-HELEN Onronn. 

